.box {
    width: 300px
}

.box button {
    width: 100%;
}

.input-field {
    width: 280px;
}

.row {
    margin: 0 10px;
    display: block;
}

/*desktop*/
@media only screen and (min-width: 768px) {

    .box {
        width: 720px;
    }

    .row {
        margin: 18px 0;
        display: flex;
    }

    .input-field {
        width: 340px;
    }

    .left {
        margin-right: 40px;
    }
}